Prof Ehrlich received early inspiration to study ecology. When in his high school years he read William Vogt's Road to Surivival, an early study of the problem of rapid population growth and food production. He graduated in zoology from the University of Pennsylvania and took MA and Ph.D. degrees from the University of Kansas. He became a full professor of biology at Stanford University and Bing professor of population studies from 1976. Though much of his research was done in the field of entomology, Ehrlich's overriding concern became unchecked population growth. He was concerned that humanity treat the Earth as a spaceship with limited resources and a heavily burdened life-support system; otherwise, he feared, “mankind will breed itself into oblivion.” He published a distillation of his many articles and lectures on the subject in The Population Bomb (1968) and wrote hundreds of papers and articles on the subject.

The Centre for the Study of Existential Risk is an interdisciplinary research centre at CRASSH within the University of Cambridge dedicated to the study and mitigation of risks that could lead to human extinction or civilisational collapse.